This is a prospective, open-label trial to evaluate efficacy for delaying ossification and improving inflammation of celebrex treatment on active ankylosing spondylitis (AS). Subjects will be randomly divided into three groups (Enbrel group, Celebrex group and Enbrel plus Celebrex group) and receive responsable treatment for 54 weeks. Clinical response assessment, laboratory assessment and radiology assessment will be recorded. Primary endpoints are the magnetic resonance imaging (MRI) Spondyloarthritis Research Consortium of Canada (SPARCC) score and the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) of spine and sacroiliac(SI) joint, as well as the Assessment of SpondyloArthritis International Society (ASAS)20 response rate. Secondary Endpoints include ASAS20, ASAS40, ASAS70 and ASAS5/6 response rate on each visit and other clinical indexes.